figure



Aug. 1, 1961 B. F. MIESSNER TUNED-VIBRATOR MUSICAL INSTRUMENT OriginalFiled Feb. 1, 1955 2 Sheets-Sheet 1 INVENTOR fieniamznfflre snez- BY TAug. 1, 1961 B. F. MIESSNER 2,994,239

TUNED-VIBRATOR MUSICAL INSTRUMENT Original Filed Feb. 1, 1955 2Sheets-Sheet 2 my: I

INVENTOR 4 5 as i g g g ii Patented Aug. 1, 1961 2,994,239TUNED-VIBRATOR MUSICAL INSTRUMENT Benjamin F. Miessner, HardingTownship, Morris County, N.J., assignor, by mesne assignments, to ThegVfilirlitzer Company, Chicago, 13]., a corporation of Originalapplication Feb. 1, 1955, Ser. No. 485,471. Di-

vided and this application May 22, 1957, Ser. No. 660,787

6 Claims. (Cl. 841.04)

This invention relates to musical instruments of the type wherein tunedvibrators are impulsively excited into vibration, from which vibrationsthe output tones of the instrument are translated. The particularinstrument illustrated is arranged so that the vibrations of thevibrators, which are fixed-free reeds, are first translated intoelectric oscillations from which the output tones are in turntranslated, but in certain of its aspects my invention is not solimited.

In various United States patents heretofore issued to me, including No.2,767,608 issued October 23, 1956, I have disclosed simplifiedvibrator-exciting actions of the percussive variety, wherein for eachnote a respective hammer is key-propelled to strike the respectivevibrator, from which it thereupon rebounds, and wherein a rerebound ofthe hammer from its propelling means, with an attendant re-striking ofthe vibrator, is precluded in one or another simple manner. The presentinvention comprises an alternative and likewise especially simplevibrator-exciting action achieving these results.

In previous devices I have disclosed, for an instrument employing aprogression of tuned fixed-free reeds extending from suitable basemeans, an arrangement of the base means and reeds which minimizes theunwanted transfer of vibratory energy from an excited reed to one ormore of the other reeds of the instrument. The present inventioncomprises an arrangement of the base means and reeds which still furtherminimizes such transfer of energy.

It is an lobject of my invention to provide a simple vibrator-excitingaction in which the re-rebound of the hammer to re-strike the vibratoris precluded in an effective and novel manner.

It is an object to provide a generally improved and simplifiedvibrator-exciting action.

It is an object of the invention to provide an improved arrangement ofbase means and reeds for minimizing the transfer of vibratory energyfrom an excited reed.

'It is a general object to provide an improved tunedvibrator musicalinstrument, and in particular an improved such instrument of the pianotype.

Other and allied objects will more fully appear from the followingdescription and the appended claims.

In the description of the invention hereinafter set forth reference ishad to the accompanying drawings, in which FIGURE 1 is a verticalsectional view of an electronic piano embodying my invention (line 11 ofFIG- URE 2) indicating the plane along which FIGURE 1 is taken;

FIGURE 2 is a horizontal view taken looking upwardly toward the planeindicated by the line 22 of FIGURE 1 (or a vertical view seen whenlooking rearwardly toward the cover 6 of the instrument when the coveris in raised position) and, for simplicity, showing only a few of thereeds FIGURE 3 is an enlarged vertical view, in section, taken along theline 3-3 \of FIGURE 1;

FIGURE 3:: is an enlarged fragmentary showing of a portion of FIGURE 4;

FIGURE 4 is a horizontal sectional view taken along the line 44 ofFIGURE 3;

FIGURE 4a is an enlarged sectional view taken along the line 4a-4a ofFIGURE 4;

FIGURE 5 is a horizontal sectional view taken along line 55 of FIGURE 3;

FIGURE 6 is an enlarged fragmentary view, partly in section, of aportion of FIGURE 1;

FIGURE 7 is a horizontal sectional view taken along line '7-7 of FIGURE6;

FIGURE 8 is an enlarged view of a righthand portion of FIGURE 2.

The drawings illustrate a 73-note instrument, but it will be understoodthat this is by way of illustration only.

In FIGURE 1 the elements 1, 2, 3 and 4 respectively represent righthandend, back, bottom and front portions of the cabinet for the instrument,these portions together with the lefthand end portion (not shown) beingfor example permanently secured together. A removable sloping fall board5 may extend between the two end portions, while a cover 6 may be hingedat its rear to the top of the back portion 2. The reeds and pick-ups maybe carried by the bottom of the cover '6, the hammers may be supportedby the back portion 2, and the hammer-actuating keys may be supported onthe bottom portion 3.

The reeds appear as 10; their mounting, the translation of theirvibrations, and related matters are dealt with below. The excitation ofeach reed is by a respective hammer 11 positioned therebelow, the head12 of the hammer being propellable upwardly to strike the reed(typically, at approximately the mid-reed nodal point for the thirdpartial vibration of the reed). The hammer head 12 may consist of achisel-shaped block of wood, preferably covered with felt, or spongerubber, \of progressively greater thickness the lower the frequency ofthe associated reed. The head 12 is aflixed to the forward extremity ofa shank 13, which is preferably of rectangular cross-section with themajor dimension of that section vertically disposed. The rear extremityof the shank 13 is in turn secured in the butt 14, which is pivoted at18 to flange 15. All of the flanges 15 are secured on top of atransverse rail 16 fixed to and extending forwardly from the cabinetback 2.

It may be mentioned that the material of the covering of the hammer headmay desirably be characterized by some viscosity, to aid in the dampingof upper partials of the reed vibration during the short period ofhammerhead contact with reed.

Each hammer is propelled to strike the respective reed by a respectivekey 20, acting through a respective controlled rate coupling member 30.The keys 20 may be pivoted about conventional pins 21, each key restingon a stack 22 of washers surrounding its respective pin, and may beguided by conventional front guide pins 23 each surrounded by aconventional stack 24 of washers forming a front-end downstop. The rearend of each key is bifurcated by a vertical slot 25 (see FIGURE 9),which freely embraces a respective post 26 screwed into the cabinetbottom 3 and having an enlarged head 27 immediately under which may beprovided a thin slightly viscous and elastic washer 28; the head 27 andwasher 28 form an upstop for the rear end of the respective key. Therelative adjustments of this rear-end upstop 2728 (effected by rotationof post 26) and of the front-end downstop (effected by choice of Washerthicknesses) are such that when the key is operated the primarilyeffective stop is the rear-end upstop 2728the front-end downstop being asecondary one whose function is to limit deformation of the key whichmay result from front-end finger pressure continued after the rearendupstop has acted.

Near its rear extremity each key carries a respective capstan member 31screwed into the key (fully seen in FIGURE 6). A little above the keytop this member may have the enlarged hex portion 32 engageable by awrench for vertical adjustment of the capstan member 31. From the hexportion 32 upwardly the capstan member 31 may consist of a rod 33preferably quite smoothly cylindrical excepting for a longitudinal flat34 several thousandths of an inch wide (shown in exaggerated width inFIGURE 6).

The respective controlled rate coupling member 30 may comprise avertically disposed cylinder 36 having, up wardly from its bottom, acircular central bore closely fitting about the rod 33 (excepting forthe flat 34 of the latter) but slidable therealong (which action may beaided by a light film of silicone grease on the rod), the upper end ofthe member 30 being solid and exteriorly rounded into substantiallyhemispherical configuration. Normally the lower extremity of thecylinder 30; rests on the capstan hex portion 32, through theintermediary of a quite thin slightly viscous and elastic washer 35-andwhen the cylinder 30 so rests the air chamber 36,. formed between thebore of the cylinder and rod 33 at the top of the latter, may be ofquite small vertical dimension. Normally the upper end of each couplingmember 30 rests the forward portion of the respective hammer butt 14, ifdesired through the intedmediary of a quite thin layer 17 of slightlyviscous and elastic material secured to the bottom of the hammer butt.When the respective hammer butt so rests the lower extremity of therespective hammer head 12 is preferably slightly spaced above a felt pad29 secured therebelow on the top of the respective key 20.

Operation of the key 20 (i.e., depression of its forward extremity bythe finger), if carried out extremely slowly, will of course raise thecapstan member 31 and coupling member 30 without disturbance of thenormal interrelationship between the latter members, and will swing thehammer butt upwardly about its pivot without any breaking of the contactof the butt with the coupling member. Preferably the components are sogeometrically interrelated that this raising will continue to, but bestopped (by the upstop 2.7-4.8) at, a position of the hammer headslightly spaced from the bottom of the respective reed 10. No impact ofhammer head with reed will occurjust as there occurs in the,conventional piano no hammer-string impact when the key is extremelyslowly I operated. When, however, the key 20 is operated with anysubstantial velocity, its own sudden stoppage by the upstop 2728 willnot be accompanied by stoppage of either the coupling member 30 or thehammer 11-. The hammer will continue under its own momentum, and withnegligible change in velocity, to strike and rebound downwardly from thereed. correspondingly the coupling member 30 will continue upwardlyunder its own momentumbut in the case of this member there is asubstantial and steady loss of velocity as the energy is dissipated at aslow rate, since this coupling-member movement can only occur with anenlargement of the air chamber 36, which can only occur with a flow ofair thereinto along the narrow passage 33a for-med between the bore ofthe coupling member '30 and the flat 34, which in turn involvessubstantial energy dissipation through air friction.

Assuming the key remains operated and the capstan member 31 thus in anelevated position, then in the relatively high-velocity rebound of thehammer from the reed its downwardly moving butt 14 will quickly comeinto impact (through 17 if employed) against the still-rising but nowrelatively low-velocity coupling member 30. I have found it desirable tomake the mass of the coupling member several times the effective mass ofthe hammer (i.e., the hammer mass as seen at the region of contactbetween hammer and coupling member). If this be done, the conditions atthe time of impact will be such that at the instant after impact thehammer velocity will be very small, while the coupling member willpossess most of the kinetic energy previously 'in the rebounding hammerand will itself be in downward motion toward its normal relationship tothe capstan member 31a motion which involves the diminution of the airchamber 36, which can only occur with a flow of air therefrom along thenarrow passageway formed as abovementioned between the bore of thecoupling member and flat 34, which in turn involves substantial energydissipation. Thus although the coupling member while the key remainsoperated is in a region where it will be struck by the reboundinghammer, a re-rebound of the hammer from it to re-strike the reed whichwould occur with all higher-velocity key operations in a conventionalsystem of this general no-escapement type-is precluded by the transferof the rebounding hammers kinetic energy to the coupling member and theharmless dissipation from the coupling member of that energy.

It will be understood that a function of the early enlargement of theair chamber 36 is to prepare it for its later diminution and that afunction of the energy dissipation during that enlargement is the rapiddeceleration of the upwardly moving coupling member, while the functionof the energy dissipation in the lat-er air-chamber diminution is theultimate one (of precluding hammer rebound) just outlined.

In a preferred embodiment of the vibrator-exciting action above outlinedI minimize incidental compliances which at the time of impact of therebounding hammer against the coupling member might yield and therebydivert from the coupling member some of the kinetic energy whichdesirably is transferred from hammer to it for harmless dissipation asoutlined above. Thus I prefer to avoid the use of felt or similarbushings at the pivoting point 13 of butt 14 to flange 1-5, and to useinstead a relatively large-diameter brass pivoting pin; I prefer to usethe vertically stiif hammer stem described above; I prefer to minimizethe compliance of (or even to omit altogether) the thin washer 35 underthe coupling cylinder, and likewise as to the layer 17 above that member(on the bottom of the hammer butt); I prefer to omit yieldable elementsfrom the washer stacks 22 about the pivots 21; and I prefer to use astiff material for the keys 2t themselves.

In certain aspects the vibrator-exciting action just outlined bas somesimilarities to those described in US. Patent No. 2,767,608 issued to meOctober 23, 1956, and in my co-pending application Serial No. 376,543,filed August 26, 1953 now Patent No. 2,813,447 (which is acontinuation-in-part of a prior application Serial No. 292,096, filedJune 6, i952 and since abandoned), but there are several distinctions ofimportance.

Attention may now be directed to the mounting of the reeds 10, thetranslation of their vibrations, etc.

The reeds, being of the fixed-free variety, are of course supported incantilever. The base of each reed is perferably surrounded by a plug 41of deformable material, and this plug is axially force-fitted into ahorizontal hole 42 in an appropriate base member so that the reedeffectively extends horizontally from the base memberthe base memberappearing in section in FIGURE 1 being 43. This structure and method ofmounting each reed to a basewhose advantages comprise exceptionallyrigid, dissipationless and determinate basing of each reed-are known.

The base member 43 does not support all the reeds of the instrument. Foran instrument of this general character, the subdivision of the totalbase means into a plurality of individual base members each supporting arespective series or group of sequentially tuned reeds is so carried outthat each individual base member has a lowest natural frequency ofvibration higher than the fundamental frequency of any reed extendingtherefrom.

In accordance with the present invention a further limitation isobserved: that the fundamental frequency of any (in effect, of thehighest-frequency) reed secured to any base member shall be lower thanthe second-partial frequency of any other (in effect, of thelowest-frequency) reed secured to that base member. I have found thislimitation important to avoid the possibility that thefundamental-frequency energy of a reed be dissipated by transfer of thatenergy to second-partial-frequency vibration of another reed secured tothe same base member. Since the ratio of second-partial frequency tofundamental frequency in a normal reed without special shaping,aperturing or the like is 6.27, and since even with such practises ittends to remain at least 6.0, this specification is readily met forexample by limiting the fundamental-frequency ratio between highestandlowest-frequency reeds secured to any one base member to less than6.0-or, in the tempered scale, to some 31 progressively tuned reeds.

Accordingly in the drawings it will be seen that the base member 43carries the thirty-one lowest-frequency reeds, the base member 44carries the twenty-four midfrequency reeds, and the base member 45carries the eighteen highest-frequency reedsit being understood thateach base member individually obeys the specification set forth in thenext-to-last preceding paragraph.

All three base members are indivdually vibrationally insulated to someextent from the cover 6 by which they are supported and, since they maybe devoid of any vibrational intercoupling other than through the cover,they may accordingly be considered as vibrationally insulated from eachother to a substantial extent. In connection with their mounting, thereis secured to the bottom of the cover 6 a transverse metal plate 8 abovethe positions to be occupied by the base members. Extending upwardlyfrom each base member through respective oversize holes 9 in the plate 8and into still larger holes 7 in the cover are a pair of studs 46 eachscrewed into the base member, one near each end of the latter. As bestseen in FIGURE 3, each stud terminates in an enlarged head 47,underneath which may be a metal washer 48. About each stud, between thewasher and plate 8, there is disposed a conically spiralled compressionspring 49. One half. of the weight of each base member appears at arespective spring 49, as a compressing force exerted thereon through therespective washer 48, each pair of these springs thus providing themounting of a respective one of the base members.

The studs 46 are so located in the front-and-back dimension that thebase members will have limited tendencies to rock either forwardly orrearwardly, and such tendencies are in any event restrained by strips 50of sponge rubber or the like placed between the base members and plate 8near the front and the back edges of the latter (each base member beingin effect floated by the two respective springs 49 and the sponge rubberstrips 50 just mentioned). There is, however, ample opportunity forsufiicient rocking of each base member in response to forces appliedthereto so that each reed is to some extent vibrationally coupled to allother reeds on the same base member-thus simulating the coupling whichexists in the conventional piano between the strings of different notes.If desired, this effect may be carried further by deliberatelyintroducing a modest amount (though it should not be too large) ofcoupling between the three base members, over and above that whichoccurs through their mounting to the single cover.

Each of the base members 43, 44 and 45 may comprise a main metalportion, for example of relatively hard aluminum, and a portion ofinsulating material appended to the main portion. The cross-section ofthe metal portion of the low-frequency base member 43 may be of theshape of an inverted L whose horizontal leg is forwardly directed, is ofappreciable and constant vertical dimension, and is of length or forwardextent varying from a maximum at the lefthand extremity, to a moderatevalue at the righthand extremity, of the member 43and whose vertical legis of constant height and of thickness varying from a minimum at thelefthand extremity, to a substantial value at the righthand extremity,of the member 43. The cross-section of the metal portion of the basemember 44 may likewise be of the shape of an inverted L, and at thelefthand extremity of the base member 44 the dimensions of the legs ofthe L may be similar to those found at the righthand extremity of member43; proceeding rightwardly, the length of the horizontal leg maycontinue to diminish, while the thickness of the vertical leg maycontinue to increase, for example so that at the righthand extremity ofthe base member 44 the cross-section of the metal portion has become asimple thick I. At the lefthand extremity of the base member 45 itsmetal portion may have the crosssection of a simple thick I, for examplesimilar to the cross-section of the righthand extremity of member 44;proceeding rightwardly, the upper portion may be cut away in front to asmall and progressive degree, so that at its righthand extremity themetal portion of the base member 45 may have a cross-section of theshape of an upright L (as indicated by the solid and dotted lines 45' inFIGURE 1).

It is in the vertical legs of the base members that the reeds 10 aresecured (through plugs 41 as above described) and from which they extendforwardly. It will of course be understood that with a constant widthand thicknesswhich I prefer to employ for at least the reeds extendingfrom base members 43 and 44then for the required progressive tuning thereed lengths will decrease progressively from a maximum at the lefthandextremity of base member 43 to a relatively short length at therighthand extremity of base member 44. I prefer to maintain thelongitudinal mid-points (more precisely, the mid-reeds nodal points forthird partial vibration) of all the reeds in a straight alignmenttransverse of the instrumentthis being so that the hammers, which Iprefer to have strike the reeds in each instance at this position, maybe arranged in a straight transverse lineand I arrange the frontsurfaces of the vertical legs of base members 43 and 44 in a gradualcurve appropriate to that maintenance. At the same time the rearsurfaces of those legs may lie in a transverse vertical planewhich ispermitted by the thickness specifications set forth in the precedingparagraph.

The progressive decrease of reed length (and with it the curving of thefront surface of the vertical leg of the supporting base member) may becontinued throughout the highest-frequency group of reeds (and theirsupporting base member 45) as a sole way of accomplishing the requiredprogressive tuning throughout this group. Because of the relativelyshort reed-length dimension already reached at the righthand extremityof base member 44, however, I prefer to minimize the further reductionof reed length throughout that highest-frequency groupsupplementing theeffect of a small length reduction, in achieving the requiredprogressive increase in frequency, by making the sides of the reedsoblique and the free ends thus narrower in progressively increasingdegree toward the righthand extremity of the base member 45, as seen inFIGURE 8. A further expedient which may be resorted to, in minimizingthe reduction of reed length throughout this highest-frequency group, isof course a progressive increase in the thickness of the reeds.

The insulating portions of the base members are designated as 53, 54 and55, respectively; each of them may extend forwardly from the upperforward surface of the respective metal base-member portion. (Each of 53and 54 may form a forward projection of the horizontal leg of therespective metal portion of 43 or 44, and 55 may form a forwardprojection from the cut-away upper part of 45.) In turn the forward partof each of the insulating portions 53, 54 and 55 may conveniently be cutaway at the top (as seen in FIGURE 1) to reduce somewhat theforward-part vertical thickness. It is in this forward part of thebase-member insulating portions that the pick-ups are mounted.

Tone-terminating dampers may be provided for the respective reeds(optionally excepting the very highestfrequency ones). The dampersproper, one of which may be seen in FIGURE 1 and which are designated56, may each consist of a small pad of relatively soft material,preferably such as mohair which presents an active surface of generallyparallel and closely spaced outwardly extending hairs. Each damper 56may be secured on the rear upper surface of a respective generallyvertical spring 57, of which the lower portion is secured to a rail 60referred to below. Normally each damper is lightly biased by itsassociated spring 57 into contact of its active surface with the free(forward) end of a respective reed 10. When in this relationship to thatreed it will effectively suppress any significant vibration of thereed-and if brought into that relationship to the reed while the reed isvibrating it will effectively and promptly terminate that vibration.

When there is operated the key associated with a reed against which arespective damper 56 is biased, for excitation of that reed, it is ofcourse necesary that the damper be removed from contact with the reed.To accomplish this each such key may be provided, somewhat behind itspivot 21, with an upstanding heavy-wire arm 58 extending to a positionclosely spaced behind the normal position of the mid-portion of therespective damper spring 57, and there folded over into a shorthorizontal portion 59. When the key is operated the arm portion 59 willbe rocked diagonally upwardly and forwardly, and in this movement willimpinge against and move forwardly the respective damper spring 57, thusplacing the respective damper 56 out of contact with the respectivereeda condition which normally will be maintained until release of thekey, whereupon the damper will return to contact with the reed and willterminate its vibration.

To provide the conventional loud pedal action all the dampers maycollectively be removed from contact with their respective reeds. Tothis end the rail 60-whose rear surface may be a gradual curveconforming to the similar curve formed by the free ends of the reedsmayhave a straight forward edge which in turn is inset into aU-cross-section channel member 61. The assembly 60-61 at its extremitiesmay be pivoted to suitable standards, the righthand one of which appearsin FIGURE 1 as 63.

The assembly 60-61 may be biased about its pivots (counterclockwise asseen in FIGURE 1) to a predetermined angular position (typically thatshown in FIGURE 1) by suitable biasing and stop means (not shown). Theassembly 6061 may be rocked against its bias (i.e., clockwise as seen inFIGURE l)thus removing all dampers collectively from contact with theirassociated reeds-by downward longitudinal movement of a rod 67 which atits upper extremity is loosely secured to an arm 63 extending forwardlyfrom the channel member 611. Such downward movement of the rod 67 may beeffected in any convenient manner, most typically by a pedal (not shown)with which its lower extremity may be suitably associated.

I have found it highly desirable in the production of the most pianistictones from impulsively excited fixedfree reeds-whose upper-partialvibrations (i.e., all above the first, or fundamental) are well known tobe normally inharmonically related to the fundamentalobserve severalspecifications:

A. To utilize means in the mechanical system which if formed by theexciting means and the vibrator to substantially eliminate from thetranslated oscillations an inharmonic component corresponding to one ofthe lowernumbered of the upper partials at which the reed tends tovibratepreferably (if the preference under B beloW be followed) thethird partial;

B. To arrange the mechanico-electrical system which is formed by thepick-up device and a portion of the vibrator so that in it is performedthe function of substantially eliminating from the-translatedoscillations an inharmonic component corresponding to one of thelowernumbered of the upper partials at which the reed tends tovibrate-preferably the second partial;

C. To arrange the mechanico-electrical system abovementioned so that byit is performed the function of introducing, into the electricoscillations which it translates from the reed vibrations, a series ofupper partials harmonically related to the fundamentalpreferably aseries which diminishes in composite magnitude (relative to themagnitude of the fundamental) as the vibration of the reed dies awayafter its impulse excitation; and

D. To arrange the mechanico-electrical system abovementioned so that thegreater deformations of the reed attendant on high-amplitude vibration,though involving quite inharmonic partials, are utilized to enhance thegeneration of the abovementioned harmonically related upper partials, aswell as to enhance the translation of the fundamental, in the electricoscillations during the very initial instants following the impulseexcitation of the reed.

Specifications A and B, taken together and utilized with respect to thesecond and third reed-vibration partials, serve the highly importantfunction of rendering harmless the significant ones of the inharmonic(i.e., all upper) partials at which the reed tends to vibratesincepartials above the third are normally sutliciently weak so that theirtranslation has a negligible deleterious effect on output tone. Statedin other words, they cause the reedthough actually still excited in thesimple impulsive manner required for a pianistic type of tonetoapproximate in its effect a vibrator whose vibration is free of partialdevelopment (i.e., whose vibration occurs only at its fundamentalfrequency).

The function just mentioned-highly important since substantialinharmonic components, especially continuing (as distinguished fromtransient) ones, are intolerable in tones intended to be pianisticw0uldresulft, taken alone, in an unusably dull tone, quite unpianisticbecause it would lack the rich development of upper partialsharmonically related to the fundamental which is characteristic of thepiano. It is to cure this lack, by creating just such a rich developmentof harmonic upper partials, that specification C is combined with A andB.

It will be convenient first to describe the pick-up means and how thestructure meets specifications A, B, and C, and then to bring out theimportance of specification D and how the structure meets it.

Specification C may be met by arranging the pick-up means so that it isprincipally influenced by an edge portion of the reed, which preferablywill most fully influence it twice in each cycle of vibration atsubstantial amplitude-it being preferably so arranged that the instanceof greatest influence, through bicyclic, are never separated byprecisely degrees (thus avoiding pure double-frequency translation).Reference being had to FIGURES 3, 3a, 4 and 4a, there will be seen foreach reed a pickup means 70. Each such pick-up means may comprise athreaded portion 73 conveniently passing vertically through the forwardpart of the associated base-member insulating portion (e.g., through theforward part of 53) and there anchored by means of two nuts 74 threadedon the portion 73 and tightened against the base-member insulatingportion, one on top and the other on the bottom. Each pick-up means mayfurther comprise a rod portion 72 preferably of reduced diameter forminga downward projection of the threaded portion, and may finally comprisean active pick-up portion 71typically in the form of an abruptenlargement of the rod portion at its end into a thin transverse endplate (for example, of thickness generally similar to that of theassociated reed). Seen in plan view of reed and end plate (e.g., inFIGURE 3a), the end plate 71 is closely spaced from an edge portion ofthe reed. Vertically, the pick-up means may be so adjusted (by nuts 74)that the end plate 71 is very nearly at the level of the reed when the 9latter is in its at-r est position, for example (see FIGURE 3) so thatits central plane approximately coincides with the plane of the bottomof the 'at-rest reed.

It is of course desirable that the natural frequency of each pick-updevice be higher than the fundamental frequency of the highest-frequencyreed of the instrument. It is further desirable that the material besoft enough to permit accurate placement of the end plate 71horizontally, relative to the reed, by slight bendings of the rodportion 72, preferably effected with the aid of an appropriate bendingtool.

It will be understood (i) that when the reed moves upwardly the capacitybetween it and the end plate 71 will progressively reduce; that as thereed moves downwardly from an upward excursion that capicity willprogressively increase, reaching its original value when the reedreaches its at-rest position; that as the reed continues to movedownwardly that capacity will at the very first still further increasesomewhat, to a maximum when the reed and end plate are in alignment(i.e., when the central planes of the two coincide), and will thenprogressively decrease; and that as the reed moves upwardly from adownward excursion that capacity will progressively increase, reachingits abovementioned maximum when the central planes of reed and end platecoincide, and will then decrease to reach its somewhat smaller originalvalue when the reed reaches its at-rest position this analysis of courseassuming that the reed movement is of suflicient amplitude so that inits downward excursion it proceeds beyond a position of alignment withthe end plate 71. It will further be understood (ii) that the higher theamplitude of reed movement, or vibration, and thus the greater itsvelocity in passing its positions of maximum capacity abovementioned,then in the waveform of the capacity variations the greater will be thesteepness of the approaches to and recessions from maximum capacity. Itwill still further be understood (iii) that if the reed be vibrating atvery high amplitude the intra-cyclic instants of maximum capacity-bothoccurring in the downward excursion half-cycle-will be separated byalmost (but never fully) 180 degrees; that as the amplitude reduces thatseparation will reduce; and that when the reducing amplitude has reacheda value only sufficient (at the peak of the downward excursion) to alignthe reed with the end plate that separation will have reached zeroafterwhich there will be in each cycle only one instant of maximum capacity.

As will hereinafter more fully appear, with this type of pick-up meansthe translated oscillations are a function of the variations of thecapacity between the reed and the pick-up means. Also, as is wellunderstood, an intra-cyclic departure from pure sinusoidal character, ifrepeated from cycle to cycle (subject to no more than minute amplitudeshifts from one cycle to the next) gives rise to the generation ofpartials which are limited to integral multiples in frequency, or trueharmonics, of the fundamental. Accordingly it is the action described in(i) above (in fully understanding which (ii) and (iii) above arehelpful) which meets the basic portion of specification Cthat thepick-up means, in its translating action, introduce into the translatedoscillations a series of upper partials harmonically related to thefundamental. Further, it is the actions described in (ii) and (iii)above which meet the supplementary portion of specification Cthat theseries of harmonic upper partials diminish in composite magnitude as thevibration of the reed dies away (magnitude being used in the sense ofamplitude relative to the amplitude of the fundamental).

In the structure specifically illustrated in the drawings the edgeportion of the reed which principally influences the active portion ofthe pick-up (i.e., end plate 71) is an internal edge portion, createdfor example by piercing the reed with a somewhat elongated hole 80. Theouter portion (i.e., the portion toward the free extremity of the reed)of the periphery of the hole may, for example 10 and as illustrated inFIGURE 3a, be of semicircular for mation, and it is from this portionthat the active pick-up portion or end plate 71which in this case mayfor example be circularis closely spaced. In FIGURE 3a the dash-dot line79 may be taken as very approximately illustrating the region,longitudinally of the reed, of average influence of the reed on thepick-up. To meet specification B this region, as to each reed, may mostdesirably be at the longitudinal position of the node for the secondpartial of the reed vibration. In the case of an unpierced reed ofuniform cross-section this node falls at a position removed from thebase of theh reed by approximately 78% (and from the free end of thereed by approximately 22% of the reed length-and the piercing of thereed appears to make no first-order change of this position, so that apositioning of the hole to bring the line of average influence of reedon pick-up at a position removed from the base of the reed byapproximately 78% of the reed length represents a close compliance withspecification B.

It is to meet specification A that the hammers have been called forabove preferably to strike the reed at the mid-reed node for thethird-partial reed vibration which node in the case of an unpierced anduniform cross-section reed falls almost precisely at the longitudinalmid-point of the reed, and is not substantially altered by the piercing.

It will of course be understood that the manner in which the mid-reednodal striking of the reed meets specification Ai.e., in which itsubstantially eliminates from the translated oscillations an inharmoniccomponent corresponding to the third partial at which the reed tends tovibrate-is by substantially eliminating the presence of that partial inthe reed vibrations, on a selective basis. The difference between thisand each of the other means of meeting specification A above referred towill be apparent.

When a fixed-free reed is vibrated at high amplitudewhich is the caseinitially after strong excitation-at a plurality of its partialfrequencies the deformation attendant on the upper-partial vibrationcomponents produces an effective shortening of the reed; this might betermed a temporary or dynamic shortening. Considering the first-partial(or fundamental) vibration, which is the one of course relied on in theabovementioned functioning of the structure, this dynamic shorteningwill temporarily increase the spacing of the locus of the vibrating-reedextremity from any pick-up located just beyond that extremity. Since theefficiency of translation is a sharp inverse function of such spacing,there takes place during the initial high-amplitude vibration a verynoticeable reduction of translation eflioiency. Thus, with a pickuplocated just beyond the free extremity of the reed, there can and doesoccur an actually observable increase of amplitude of the translatedoscillations during the early instants after reed excitation, as thedynamic deformation subsides and the translation efliciency thereforeincreases.

This time is one when, in a normal piano, a very notice able decrementof the output sound occurs; indeed, an especially high initialdecrementi.e., decrement during the first few instants of a toneis astrong distinguishing feature of piano tone.

By arranging the pick-up means so that the edge portion of the reedwhich most actively influences it is a longitudinally intermediateportion, or portion other than the free extremity of the reed-forexample, by arranging it so that that edge portion of the reed is aside-edge portionthe disadvantage just discussed is obviated. Thereby aworthwhile improvement in respect of toneinception characteristics isachieved.

I have found, however, that important still further improvement ispossible. It is achieved by arranging the pick-up means so that thelocus of the portion of the reed which principally influences itinsteadof being brought further away from it, or left unchanged, by the dynamicshortening of the reedis by that dynamic shortening brought closer toit. It is for this reason that I have employed, for the portion ofthe'reed which principally influences the pick-up means, an internal edgeportion-and have selected for that edge portion the outer (rather thanthe inner) peripheral portion of the hole 80. This represents alongitudinally intermediate edge portion specially selected for positiveadditional advantages.

It will be understood that the effect of this favorable utilization ofthe dynamic shortening of the reed during the early instants followingthe excitation of the reed is not only to enhance the translation of thefundamental (thereby increasing the initial decrement, as is desirable),but also then to increase the generation of harmonically related upperpartialssince the steepness of the waveform of capacity variation islikewise increased by this utilization. It is so that specification D ismet. This is of especial importance since a distinguishing feature ofpiano tone, over and above the high initial decrement, is a very initialburst of momentarily accentuated harmonic development.

The pick-up means have so far been described without particularlimitation as to type-and as to broader aspects none is intended. In amore specific aspect those disclosed are of the capacitative type(though their analogues, magnetic for example, will be readilyunderstood). For the capactitative type, in turn, no limitation as toparticular species is intended, as between those operating for exampleon a D.C., on an amplitude-modulating, or on a frequency-modulatingbasis-each of which in broad outline is well known in the art and neednot here be detailed. With the disclosed pick-up means, whatever be thespecies used, the associated electrical and electronic circuitry(including for example the associated pre-amplifier) may be formed as acompact unit 88 which, if desired and as indicated in FIGURES 1 and 2,may be physically disposed below the cover 6 behind the base members 45and 44 at the treble extremity of the instrument.

This application is a division of my co-epnding application Serial No.485,471, filed February 1, 1955, and now abandoned, which containsclaims to certain of the subject matter herein disclosed.

While I have disclosed my invention in terms of a particular embodimentthereof, it will be understood that unnecessary limitations are notthereby intended, since by the disclosure various modifications will besuggested to those skilled in the art. Such modifications will notnecessarily constitute a departure from the scope of the invention,which I undertake to express in the appended claims.

I claim:

1. A percussion-type musical instrument comprising base means, avibrator carried by said base means, a key movably mounted on said basemeans and adapted to be moved by manual engagement thereof, a hammermovably mounted on said base means for percussive engagement with saidvibrator, and a controlled rate energy dissipating coupling membercomprising a pair of relatively movable elements interfitting in energydissipating relation, the first of said elements being mounted on saidkey and the second thereof being in driving engagement with said hammer,whereby manual movement of said key to a limit position acts throughsaid coupling member to propel said hammer into engagement with saidvibrator, said hammer moving out of engagement with said coupling memberand the second element moving away from the key relative to the firstelement, said hammer upon rebounding from said vibrator re-engaging saidsecond element and moving said second element in energy dissipatingmanner relative to said first element to absorb energy of the reboundinghammer for preventing the hammer from restriking the vibrator.

2. A percussion-type musical instrument as set forth in claim 1 andfurther comprising friction energy dissipating means disposed betweensaid elements.

3. A precussion-type musical instrument as set forth in claim 2 whereinone of said elements comprises a piston and the other comprises acylinder providing a dashpot air friction type mechanism.

4. A percussion-type musical instrument as set forth in claim 3 whereinthe piston has a flat thereon providing a limited air passage betweensaid piston and said cylinder.

5. A percussion-type musical instrument as set forth in claim 1 whereinsaid vibrator is mounted at one end and is free at the oppsite end, andfurther including a damper engagable with the free end of the vibratorand a member on said key engagable with said damper for retracting saiddamper from engagement With said vibrator upon movement of said key.

6. A percussion-type musical instrument as set forth in claim 1 whereinthe vibrator is mounted above the hammer, and the hammer is mountedabove the key, said hammer moving upwardly into percussive engagementwith said vibrator and being gravitationally returned.

References Cited in the file of this patent UNITED STATES PATENTS1,544,117 Wyatt June 30, 1925 1,866,152 Cameron July 5, 1932 1,907,935Curtiss May 9, 1933 1,997,522 Jaksha Apr. 9, 1935 2,214,112 SchulzeSept. 10, 1940

